Application Service Providers
If your hard disk is packed to bursting point, the IT department is far too busy to fix your email problems, and your business can't afford to buy the tools that you'd like to develop the company website, then it's time to think about using an application service provider (ASP). Rather than installing software on each machine or server within your organization, you rent applications from the ASP, which provides remote access to the software and manages the hardware required to run the applications.
There are a lot of advantages to this approach. The havoc caused by viruses makes the idea of outsourcing your email and office suite services an attractive option. It also gives you more flexibility - you pay for applications as and when you need them, rather than investing in a lot of costly software which you're then tied to for years. Not having to worry about upgrading to the latest version of your office suite or about battling with the complexities of managing an email system, leaves businesses with more time. Time to focus on what they do best.
However, there are some potential pitfalls. To use applications remotely requires a lot of bandwidth, which is only really available from a broadband connection or a leased line to the ASP itself. It is also important to ensure that the ASP will be able to provide a secure, reliable service which will be available whenever you need it.
Providing applications and storage space for vast numbers of users requires some powerful technology on the part of the ASP. This includes security controls and data storage as well as providing the physical links to customers. For the most part, ASPs don't own the data centers that store the information. Instead, they lease space from data storage specialists. In this way, they can be confident of meeting customers' increasing storage requirements by buying more space as it's needed.
There's a wide variety of applications available foruse via ASPs. Office suite applications and email services are two of the most generic applications available through ASPs. Large, complex business applications such as enterprise resource planning tools like SAP are another popular candidate for delivery through onASP. Other business services, such as payroll andaccounting systems are also available. This is particularly beneficial to small businesses which are likely to grow quickly and don't want to deal with the problems caused by outgrowing their existing system and having to move to a high-end package. ASPs also offer a means of using specialist tools that would otherwise prove prohibitively expensive. Small businesses have the opportunity to use such toolsfor short periods of time as and when they need them, rather than having to buy the software as a permanent investment.
One of the major barriers for small businesses which want to make a start in e-commerce is ensuring that they have sufficient resources to copewith sudden large increases in customers. This means not only having adequate storage for all your customers' details, but ensuring that you have the technology in place to handle stock levels, efficient delivery and large volumes of traffic. It's very rare for an e-commerce business to handle all of these elements by itself, making this one of the best-established areas of ASP use. Being able to respond rapidly to changes in the size of your customer base and the type of product that they want to orderfrom your business, demands more flexibility than traditional software can provide.
II. Re-read the text to find the answers to these questions.
Match the items in Table A with the statements in Table B.
Table A
a Website
b ASP
с Virus
d Office suite
e Bandwidth
f Broadband
g Data centre
h SAP
Table B
i Set of standard programs used in an office
ii Facility for storing large amounts of information
iii Capacity of a network connection
iv High capacity Internet connection
v Self-replicating program
vi Common enterprise resource planning tool
vii Application service provider
viii Collection of related webpages
2 Using information from the text, mark the following as True or False:
a Software from an ASP must be installed locally on a user's computer.
b You need a high bandwidth connection to use an ASP service.
с ASPs usually use their own storage space for customers.
d Using an ASP gives you more flexibility.
e An e-commerce business usually provides all of the required technology itself.
Text 5
I. Find the answers to these questions in the following text.
1. Into what two components is the data stream split?
2. What information does an Intra frame contain?
3. What is stored in the P-frames following an l-frame?
4. What is stored in a P-frame in the case of a bouncing ball?
5. What gives the massive reduction in the amount of information needed to reproduce a video sequence?
6. Why is a new l-frame used after a few P-frames?
7. What is stored in a B-frame?
8. Why do B-frames not propagate errors?
The most common system for the compression of video is MPEG. It works like this. The single data stream off the CD-ROM is split into video and audio components, which are then decompressed using separate algorithms. The video is processed to produce individual frames as follows. Imagine a sequence of frames depicting a bouncing ball on a plain background. The very first is called an Intra Frame (I-frame). I-frames are compressed using only information in the picture itself just like conventional bitmap compression techniques like JPEG.
Following I-frames will be one or more predicted frames (P-frames). The difference between the P-frame and the I-frame it is based on is the only data that is stored for this P-frame. For example, in the case of a bouncing ball, the P picture is stored simply as a description of how the position of the ball has changed from the previous I-frame. This takes up a fraction of the space that would be used if you stored the P-frame as a picture in its own right. Shape or colour changes are also stored in the P-frame. The next P-frame may also be based on this P-frame and so on. Storing differences between the frames gives the massive reduction in the amount of information needed to reproduce the sequence. Only a few P-frames are allowed before a new I-frame is introduced into the sequence as a new reference point, since a small margin of error creeps in with each P-frame.
Between I and P-frames are bi-directional frames (B-frames), based on the nearest I or P-frames both before and after them. In our bouncing ball example, in a B-frame the picture is stored as the difference between the previous I or P-frame and the B-frame and as the difference between the B-frame and the following I or P-frame. To recreate the B-frame when playing back the sequence, the MPEG algorithm uses a combination of two references. There may be a number of B-frames between I or P-frames. No other frame is ever based on a B-frame so they don't propagate errors like P-frames.
Typically, you will have two or three Bs between Is or Ps, and perhaps three to five P-frames between Is.
II. Re-read the text to find the answers to these questions.
1 Mark the following statements as True or False:
a JPEG is the most common compression system used for video.
b P-frames only store the changes in the image.
с There is always at least one P-frame between two I-frames. d B-frames store the complete picture information.
e There can only be one B-frame between each I and P-frame. f There are typically about four P-frames between each l-frame.